/* flex布局 */
.u-f, .u-f-ac, .u-f-ajc {
    display: flex;
}

.u-f-ac, .u-f-ajc {
    align-items: center;
}

.u-f-ajc {
    justify-content: center;
}

.u-f-jsb {
    justify-content: space-between;
}

.u-f1 {
    flex: 1;
}

.u-f2 {
    flex: 2;
}

.u-f3 {
    flex: 3;
}

.u-f-column {
    flex-direction: column;
}

.u-f-l {
    justify-content: flex-start;
}

.u-f-r {
    justify-content: flex-end;
}